WASHINGTON — The Consumer Financial Protection Bureau opened up its bulging online complaint hotline files to public view last week, and the contents are startling: Though the CFPB's complaint window is open to various financial disputes — credit cards, student loans, credit reporting agencies, bank loans to consumers — by far the biggest source of complaints is home mortgages. Nearly half of all disputes reported to the agency by consumers are mortgage related — problems with payments, escrow accounts, servicing, FHA and conventional loans, home equity lines, second mortgages, reverse mortgages, loan modification delays, application foul-ups and the like.

The new database — at consumerfinance.gov and updated daily — doesn't provide the details of specific alleged misdeeds. Nor does it identify the consumers filing complaints other than by ZIP code. But it does identify the banks or mortgage lenders that are the targets of the complaints and whether they responded to the agency to try to resolve the matter.

In the vast majority of cases, lenders have responded within 15 days — often apparently to the satisfaction of their customers. When the CFPB receives a complaint, it verifies that the consumer is indeed a customer of the bank or mortgage company, but does not attempt to determine whether the allegations by the consumer have merit. It contacts the lender, provides a secure portal for a reply, then informs the consumer about the lender's response using a separate secure portal.

When the case is posted to the online database, it's catalogued as either in progress, closed, closed with an explanation, closed with monetary relief to the consumer, closed with nonmonetary relief or closed with dispute comments added to the file by the consumer indicating unhappiness with the lender's response.

Does the hotline system really work? Bob Ogle of Tucson describes himself as a big fan. He filed a complaint about a mortgage servicing company in Texas on Feb. 8 protesting a pending foreclosure action against his mother. Not only was the CFPB's response swift — the agency contacted the loan servicer immediately and obtained a response. The foreclosure was canceled and the entire dispute resolved.

However, banks and mortgage lenders aren't as thrilled about the complaint database as Ogle is. For one thing, they are named, even if the complaint ultimately turns out to have been unfounded. Also, the searchable feature of the database allows anyone to check on the number of complaints filed against any specific lender — which some large banks consider unfair given that their high volumes of transactions are almost guaranteed to generate more complaint filings than would smaller lenders.

For example, of the roughly 50,000 mortgage complaints in the database at the end of March, 15,179 — about 30 percent — named Bank of America. Another 8,030 named Wells Fargo, 2,257 were against JP Morgan Chase, and 2,147 named Citibank, all among the highest-volume mortgage originators and servicers active in the market. Nearly 3,400 named Ocwen Financial Corp., a company that specializes in servicing large portfolios of underwater, delinquent and subprime mortgages.

Richard Hunt, president and CEO of the Consumer Bankers Association, says the CFPB' s approach on this is flawed. "A better service to consumers," he said, "would have allowed for collaboration between the CFPB and financial institutions to determine if a complaint is indeed valid, prior to publication."